1. Field of the Invention
The present invention relates to a semiconductor wafer position detecting system, semiconductor device fabricating facility of using the same, and wafer position detecting method thereof, by which the position state of wafers is detected prior to performing processes in order to prevent failure in the processes.
2. Description of the Related Art
A semiconductor device fabricating facility includes vacuum chambers for performing processes such as chemical vapor deposition, etching, or metal deposition in vacuum chambers provide a clean environment and prevent wafer pollution during processing. The chamber is made of an opaque material such as metal that has sufficient strength to withstand the vacuum.
As shown in FIG. 1, a wafer W placed into the fabricating facility and supported on a chuck plate can detach from the upper surface of the chuck plate 10 if particles P (such as pieces of wafer) are left on the chuck plate 10. In addition, as shown in FIG. 2, the wafer W slips on the particles and is displaced from the predetermined position in the course of being transferred or placed on the chuck plate 10.
However, with the conventional facility it is difficult to determine whether the wafer is properly transferred to or placed on a predetermined position. Sometimes, it is necessary to open the chamber in order to confirm the position of the wafer.
Assembling or disassembling repeatedly such the vacuum chamber to verify the position of the wafer causes trouble in maintaining a vacuum in the chamber, lengths overall processing time, working hours, increasing the amount of work done, and more labor power. In addition, the repeated assembling and disassembling of the fabricating facility reduces the productivity of the fabricating facility, and wafers can be contaminated opening of the chamber.
In order to change and improve such environments, a conventional vacuum chamber fabricating facility is provided with a transparent window to see into the chamber. However, this configuration causes a problem that a user cannot confirm whether a wafer has been damaged, e.g., in the edge of wafer broken or cracked.
Such a transparent window in the predetermined portion of the chamber becomes covered with deposited polymers that are generated during processes and becomes opaque. It is impossible to confirm whether wafers are damaged even in instances where a plurality of wafers are folded or broken.
The transparent window also does not permit a user to confirm whether wafers in the fabricating facility are damaged or broken or contaminated by pollutants including particles.
It is an object of the present invention to provide a semiconductor wafer position detecting system, chuck assembly of using the same, and semiconductor wafer position detecting method thereof, which allows one to confirm whether wafers are normally transferred, whether wafers are properly positioned, and whether wafers have detached from the chuck plate without disassembling or assembling the fabricating facility. Thereby, the number of times in assembling and disassembling the fabricating facility, working hours and the amount of work done can be reduced, so that the rate of operation and productivity of the fabricating facility are increased and wafers are prevented from being contaminated.
In order to achieve the object, the semiconductor wafer position detecting system includes:
a chuck plate formed with at least one or more holes at a portion thereof on which a wafer is normally and closely placed;
a fluid line connected between a lower portion of each of the holes and a fluid driving means;
at least one or more valves provided on the fluid line to control fluid flow in response to an opening/closing signal;
a sensor provided on the fluid line to detect a pressure state of the fluid;
an output device for outputting in response to an output control signal; and
a controller for selectively applying an opening/closing signal and an output control signal to the valve and output device, and detecting the position state of wafer by a measurement signal applied from the sensor.
The chuck plate upper surface includes one or more guiding grooves that communicate with the upper portion of at least one or more holes.
It is desirable that the guiding groove is formed within the region where a wafer is normally placed within the normal position of and the edge of the wafer.
The guiding groove may be formed in a radial direction or spiral direction relative to the center the wafer in the normal position, or may be formed along circumferences having different diameters relative to the center of the wafer in its normal position, or may be a combination of the radial shape, spiral shape and circumference shape.
The fluid line is configured so that the fluid flows from one side of the fluid line through the guiding groove and discharges through the other side of the fluid line after the wafer is normally placed on the center position of the chuck plate.
The sensor may use a pressure gage that measures pressure in the fluid line, or a flowmeter for detecting a flow rate of fluid in the fluid line.
It is effective that at least one or more optical sensors are further provided above and opposite to the portion of the chuck plate where the edge of wafer is placed to thereby detect the position of the edge of wafer and output the resultant signal to the controller.
The wafer detecting system further comprises a rotational driving apparatus for rotating the chuck plate in response to a rotational control signal selectively applied from the controller.
The output device is configured by combining at least one or more out of a bell giving an alarm, a lamp outputting a light signal, a monitor displaying the position state of wafer, and a switching part for selectively cutting off an electric power applied to each of the elements of the system in response to a signal generated by the controller when a wafer is improperly positioned.
The semiconductor fabricating facility provided therein with a wafer position detecting system according to another embodiment of the present invention, includes:
a chamber provided with an opening/shutting apparatus for opening or shutting the chamber in response to an opening /shutting control signal;
a chuck plate provided in the chamber to rotate and formed thereon with at least one or more holes;
a rotational driving apparatus provided under the chuck plate to rotate the chuck plate in response to a rotational control signal;
a fluid line communicated with each of the holes to form a fluid path;
a valve provided on the fluid line to control a fluid flow in response to a fluid flow control signal;
a sensor provided on the fluid line to detect a state of the fluid;
an output device for outputting in response to an output control signal; and
a controller receiving a signal of the sensor to detect the position the wafer, outputting the resultant signal to the output device and outputting the rotational control signal and fluid flow control signal to the rotational driving apparatus and valve.
It is preferred that the chamber is further provided therein with a vacuum forming apparatus for forming a vacuum state thereof.
The wafer position detecting method of the wafer position detecting system includes:
providing a chuck plate formed with at least one or more holes at a portion thereof on which a wafer is normally and closely placed; a fluid line communicated with a lower portion of each of the holes; at least one or more valves provided on the fluid line to control fluid flow in response to an opening/closing signal; a sensing means provided on the fluid line to detect a state of the fluid; an output means for outputting in response to an output control signal; and a controller for selectively applying an opening/closing signal and an output control signal to the valve and output device, and detecting the position of wafer by a measurement signal applied from the sensor.
A wafer on the chuck plate; controlling fluid to flow through the fluid line; detecting a pressure or a fluid flow state in the fluid line; checking a contact state and position state of wafer on the chuck plate according to whether a measured value is within a predetermined scope to control fluid flow through the valve; and outputting through the output device information including the measured values to the pressure or fluid flow state, set values, and probe gas supplied state.
It is effective that the wafer position detecting system further includes at least one or more optical sensors provided above the chuck plate to detect the position of the edge of the wafer. The wafer detecting method further includes the step of detecting a position of the edge of the wafer by the optical sensor prior to checking the position of wafer.
It is desirable that the wafer position detecting system further includes a rotational driving apparatus to rotate the chuck plate. The wafer position detecting method includes the step of detecting a position the edge of the wafer on the chuck plate to correspond to the optical sensor.
The wafer position detecting method further comprises the step of controlling a fluid flow by the valve when the wafer is abnormally placed.